AB MfB interview normally is in 3 stages. It also depends on the position you're being interviewed for. At the 1st stage, you guys will be given a topic to brainstorm and make a presentation all in the presence of a panel of interviewers. At the 2nd stage, another topic will be given, with the same process. All they look out for is your amount of contribution, your communication ability, logical reasoning and your teamwork. Make sure you contribute a lot. At the 3rd stage, you meet the panel personally. All the best.